A mobile terminal may be configured to perform various functions. The examples of the various functions may include a data and voice communication function, a photo or video capture function through a camera, a voice storage function, a music file reproduction function through a speaker system, an image or video display function, and the like. Some mobile terminals may include an additional function capable of implementing games, and some other mobile terminal may be implemented as a multimedia player. Moreover, recent mobile terminals receive broadcast or multicast signals to allow the user to view video or television programs.
Furthermore, the efforts for supporting and enhancing the functions of the mobile terminal have been carried out. The foregoing efforts may include adding and improving software or hardware as well as changing and improving structural elements constituting a mobile terminal.
In the conventional touch screen-based device such as a personal digital assistant (PDA), a user's interest in a touch function and a graphic function of a device was low, because an H/W basic function of the device is low. However, as a touch screen-based smart phone becomes popular and an H/W function of a device becomes high in recent years, a touch function and a graphic function visible to a user are considered as an important factor.
Generally, in a touch screen-based device, input lag is generated due to a difference between a time point to input a user's actual touch coordinate and a time point to output the input touch coordinate on a screen. In the touch screen-based device, a game is one of important applications. In case of manipulating a game character movement by moving a touch coordinate, a character movement has a response time to a finger's movement, due to touch input lag. Such delayed response time causes a user not to well-concentrate on a game.
In the touch screen-based device, a drawing application is also one of important applications. Once a user directly draws a drawing on a screen of the device using his or her finger, a stylus pen, etc., the drawing application displays a touch path on the screen using input touch coordinates. In this case, the touch path is displayed on the screen after a response time lapses from a user's touch input time point.
Due to the input lag, there occur delay of coordinate generation in a touch-related H/W, delay of coordinate processing in a touch-related S/W, delay of output due to a display refresh rate, etc. Such input lag causes a user's concentration to directly draw on paper, to be lowered.